From 4ad3ec7da3ec6eab2dd54f7dbbbae8d9b62d57d3 Mon Sep 17 00:00:00 2001
From: Michael Benfield <michaelbenfield@provable.com>
Date: Thu, 14 Nov 2024 14:33:48 -0800
Subject: [PATCH] check for empty frames

---
 interpreter/src/cursor.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/interpreter/src/cursor.rs b/interpreter/src/cursor.rs
index 223d7a11c1..0f66ceaa11 100644
--- a/interpreter/src/cursor.rs
+++ b/interpreter/src/cursor.rs
@@ -2377,6 +2377,10 @@ impl<'a> Cursor<'a> {
     /// stack. Once that has executed and we've returned to the conditional, the final step
     /// does nothing.
     pub fn step(&mut self) -> Result<StepResult> {
+        if self.frames.is_empty() {
+            halt!("no execution frames available");
+        }
+
         let Frame { element, step, user_initiated } = self.frames.last().expect("there should be a frame");
         let user_initiated = *user_initiated;
         match element {